Fluid pressure reference



Filed April 10, 1964 I REFERENCE? FIG? INPUT PRESSURE ATTORNEY UnitedStates Patent Ofilice 3,3 l3,3 l3 Patented Apr. 11, 1967 3,313,313 FLUIDPRESSURE REFERENCE Silas Katz, Silver Spring, Md, assignor to the UnitedStates of America as represented by the Secretary of the Army Filed Apr.10, 1964, Ser. No. 358,964 6 Claims. (Cl. 137-815) The inventiondescribed herein may be manufactured and used by or for the Governmentof the United States of America for governmental purposes without thepayment to me of any royalty thereon.

The present invention relates to fluid devices having no movingmechanical parts, and more particularly to purely fluid devices whichutilize the Coanda or fluid latch effect to direct the flow of a jet.

The problems of reliability and durability of control and processingsystem components under conditions of environmental extremes have led tothe development of a class of devices known as pure fluid elements.These devices are basically a plurality of ducts and channels whichcarry fluid. A typical device is constructed by cutting, forming oretching the channels in a block of solid material and covering thechannels with a coverplate, thereby closing them in on all sides Thefunction performed by a typical device would be determined by the way inwhich flow is directed through the various channels. ince there are nomoving parts through which the fluid must move, problems such as extremewear, lubrication, fatigue failure, and corrosion are substantially orcompletely eliminated.

The prior art has conceived some elaborate combinations to perform oneor another of the functions performed by the present invention such assensing ressure and flow levels, producing discrete outputs atpredetermined reference levels of pressure and flow, relievingoverpressures and regulating pressure levels. The present inventionsatisfies the need to perform these functions in one very simple andcompact component with not. a single moving part.

Therefore, an object of the present invention is to provide a purelyfluid means of sensing a pressure and fiow level in a fluid system.

Another object of the present invention is to provide a simple devicewhich gives discrete output pressures and flows when the input pressureand flow reach a predetermined reference level.

A further object of the present invention is to provide a simple andreliable purely fluid relief valve.

Still another object of the present invention is to provide anomoving-part pressure regulator.

In accordance with one aspect of the present invention these and otherobjects are accomplished by use of a device which comprises an orificenozzle which produces a jet flow into a chamber at one end of suchchamber with outlet channels located at the opposite end of the chamber.A wall located at the nozzle exit and olfset from the nozzle centerlinecauses the jet to attach to the wall and flow out the channel on thewall side. As supply pressure behind the nozzle is increased, the jetstream spreads and successively passes out the remaining outletchannels. Varying the level of pressure acting on the nozzle above areference level produces a discrete signal unaffected by downstreamloading of the device. In other words the device responds to preciselythe same predetermined input regardless of what sort of load is attachedto its output.

The foregoing and other objects of the present invention will be morefully apparent from the consideration of the following description anddrawings in which:

FIG. 1 is a sectional plan view of a device constructed in accordancewith the present invention showing a flow condition which is produced bya pressure below the desired reference level;

FIG. 2 is a sectional view of the device of FIG. 1 in which the inletpressure, and correspondingly flow, have increased above the referencelevel;

FIG. 3 shows a graph of output pressure versus input pressure; and

FIG. 4 is a sectional plan view of a device constructed in accordancewith the present invention having many outlet channels.

The fluid device of FIGS. 1 and 2 comprises .a source of varyingpressure 1, a nozzle 2 connected by a pipe 3 to the source of pressurewhich serves to deliver flow in a coherent jet stream 4 to aninteraction chamber 5, a near wall 6 located near the nozzle outlet andoffset from it with which the jet issuing from the nozzle 2 interacts,and a near wall outlet receiver channel 7 which receives the flow of thejet stream 4 on the near wall side of the chamber 5. A far channel 8 anda far wall 9 are located opposite the near wall 6 and the near receiverchannel 7.

In the condition shown in FIG. 1 there is no flow out the far receiverchannel 8 because the far wall 9 is offset a greater distance from theinlet nozzle 2 than is the near wall 6 and the flow tends, therefore, toattach to the nearer wall. A flow indicator vane 10, or other flowindicator, is located in the far outlet channel 8, and indicates a zeroflow condition. Absence of flow out the far receiver channel indicatesthat the desired reference level has not been reached at the source 1.

In the condition shown in FIG. 2 the source pressure has been increasedso that the stream 4 now spreads and leaves the device through both nearoutlet receiver 7 and far outlet receiver 8. The far offset wall 9serves to guide the flow out the far receiver channel 8. The fluid latchproduced at the far wall 9 is weak compared with the latch at the nearwall 5 so that, as the source ressure is decreased below the referencelevel, the jet stream 4 will always detach from the far wall 9 andreturn to the near wall 6 so that all the flow will go out the nearreceiver channel 7. The flow indicator 10 shows that a signal is beingproduced in the far outlet channel 8.

Placement of the far wall 9 will have an effect on the performance ofthe device but as long as it is offset farther from the nozzle 2 thanthe near wall 6 is offset, the device is operable. An oifset ratio of 3to 1 would insure dependable operation The location of the outletreceivers may be shifted about the nozzle centerline as a means oftuning the output in relation to the input signal; however, asatisfactory configuration is produced with the receivers arrayedsymmetrically about the nozzle centerline.

No external control signals are necessary to actuate the device. Thephysical characteristics of the power source create a phenomenon wheninteracting with the geometry of the device that produces the desiredfunctions without the need for controls of any sort.

FIG. 3 shows graphically the abrupt increase in pressure at the faroutput receiver 8 when the input pressure of source 1 rises above acritical reference level.

FIG. 4 is another embodiment of the present invention comprising aninlet nozzle 11 communicating with chamber 12 which has a restrictingwall 13 forming one side. A first outlet channel 14 a second outletchannel 15 and a third outlet channel 16 each receive flow signals atdiscrete predetermined levels of flow through nozzle 11 as such flow issuccessively raised to these levels. Flow through nozzle 11 is relatedto pressure level at source 17 in a known relationship which can beregulated by choice of nozzle size.

It can be seen from the foregoing that the present invention provides asimple and dependable means of sensing, indicating and regulatingpressure and flow.

O Other configurations can be imagined by a person skilled in the artwithout the necessity of further invention. For example, the far wallcould be removed entirely. In addition, in the embodiment having twooutlet channels with careful design the stream could always be directedout one side or the other but not from both sides simultaneously.

It will be apparent that the embodiments shown are only exemplary andthat various modifications can be made in construction and arrangementwithin the scope of the invention as defined in the appended claims.

I claim as my invention:

1. Apparatus responsive to increase of fluid input pressure above apredetermined level, comprising:

(a) a source of varying fluid pressure,

(b) nozzle means connected to said source for producing at the output ofsaid nozzle means a fluid jet the amplitude of which increases withincrease in the pressure of said source,

(c) a chamber connected to the output of said nozzle means for receivingsaid fluid jet,

(d) first and second output channels leading from the end of saidchamber remote from said nozzle means,

(e) the axis of said first and second output channels and of said inputnozzle lying substantially in a first plane,

(f) said chamber having a first sidewall that is substantiallycontinuous with one wall of said first output channel and having asecond sidewall that is substantially continuous with one wall of saidsecond output channel,

(g) said second sidewall being offset from the axis of said nozzle, thedistance from said second sidewall to the axis of said nozzle beinggreater than the distance from said first sidewall to the axis of saidnozzle, (h) whereby (1) fluid entering said chamber from said inputnozzle attaches itself more readily to said first sidewall than to saidsecond sidewall,

(2) substantially all fluid entering said chamber from said input nozzleleaves through said first output channel when the pressure of said fluidinput is less than a certain fixed critical value,

(3) a portion of the fluid entering said chamber from said input nozzleleaves through said second output channel only when the pressure of saidfluid input is at least equal to said critical value.

2. Apparatus in accordance with claim 1, wherein the sidewalls of saidchamber are offset from said input nozzle, the offset of said sidewallon the side of said second output channel being greater than the offseton the side of said first output channel, so that the fluid jet fromsaid nozzle tends to attach to the sidewall on the side corresponding tosaid first output channel in preference to the sidewall corresponding tosaid second output channel.

3. Apparatus in accordance with claim 2, wherein the outer portions ofthe inner walls of said first and second output channels aresubstantially straight continuations of the corresponding sidewalls ofsaid chamber.

4. Apparatus in accordance with claim 2, there being additionallyprovided at least a third output channel, said third output channelbeing positioned between said first and second output channels andhaving its axis substantially in said first plane.

5. Apparatus in accordance with claim 3, there being additionallyprovided means responsive to the presence of flow from said secondoutput channel.

6. Apparatus in accordance with claim 4, there being additionallyprovided first means responsive to the presence of flow from said thirdoutput channel and sec ond means responsive to the presence of flow fromsaid second output channel.

Reierences Cited by the Examiner UNITED STATES PATENTS 3,001,539 9/1961Hurvitz 137--81 3,159,168 12/1964 Reader 13781 3,168,897 2/1965 Adams etal 13781 3,182,674 5/1965 Horton l37-81 3,194,253 7/1965 Havee 137813,204,652 9/1965 Bauer 137-81 3,217,727 11/1965 Spyropoulos 137813,219,048 11/1965 Palrnisano 137-81 FOREIGN PATENTS 1,136,518 9/1962Germany.

M. CARY NELSON, Primary Examiner.

S. SCOTT, Assistant Examiner.

1. APPARATUS RESPONSIVE TO INCREASE OF FLUID INPUT PRESSURE ABOVE APREDETERMINED LEVEL, COMPRISING: (A) A SOURCE OF VARYING FLUID PRESSURE,(B) NOZZLE MEANS CONNECTED TO SAID SOURCE FOR PRODUCING AT THE OUTPUT OFSAID NOZZLE MEANS A FLUID JET THE AMPLITUDE OF WHICH INCREASES WITHINCREASE IN THE PRESSURE OF SAID SOURCE, (C) A CHAMBER CONNECTED TO THEOUTPUT OF SAID NOZZLE MEANS FOR RECEIVING SAID FLUID JET, (D) FIRST ANDSECOND OUTPUT CHANNELS LEADING FROM THE END OF SAID CHAMBER REMOTE FROMSAID NOZZLE MEANS, (E) THE AXIS OF SAID FIRST AND SECOND OUTPUTCHANNELS, AND OF SAID INPUT NOZZLE LYING SUBSTANTIALLY IN A FIRST PLANE,(F) SAID CHAMBER HAVING A FIRST SIDEWALL THAT IS SUBSTANTIALLYCONTINUOUS WITH ONE WALL OF SAID FIRST OUTPUT CHANNEL AND HAVING ASECOND SIDEWALL THAT IS SUBSTANTIALLY CONTINUOUS WITH ONE WALL OF SAIDSECOND OUTPUT CHANNEL, (G) SAID SECOND SIDEWALL BEING OFFSET FROM THEAXIS OF SAID NOZZLE, THE DISTANCE FROM SAID SECOND SIDEWALL TO THE AXISOF SAID NOZZLE BEING GREATER THAN THE DISTANCE FROM SAID FIRST SIDEWALLTO THE AXIS OF SAID NOZZLE, (H) WHEREBY (1) FLUID ENTERING SAID CHAMBERFROM SAID INPUT NOZZLE ATTACHES ITSELF MORE READILY TO SAID FIRSTSIDEWALL THAN TO SAID SECOND SIDEWALL, (2) SUBSTANTIALLY ALL FLUIDENTERING SAID CHAMBER FROM SAID INPUT NOZZLE LEAVES THROUGH SAID FIRSTOUTPUT CHANNEL WHEN THE PRESSURE OF SAID FLUID INPUT IS LESS THAN ACERTAIN FIXED CRITICAL VALUE, (3) A PORTION OF THE FLUID ENTERING SAIDCHAMBER FROM SAID INPUT NOZZLE LEAVES THROUGH SAID SECOND OUTPUT CHANNELONLY WHEN THE PRESSURE OF SAID FLUID INPUT IS AT LEAST EQUAL TO SAIDCRITICAL VALUE.